Human brains are wired for music. Scientists think the oldest musical instruments were flutes that date back somewhere between 67,000 and 37,000 years ago. We assume though that people were banging on wood or their thighs, or knocking two rocks together long before that. Almost anything can be a musical instrument. A case in point: [elifer5000] walked into a room containing a lot of running 3D printers, and thought it seemed musical. Next thing you know, he harnessed 3D printers as a MIDI instrument.
At a hackathon, he found some software that converts a MIDI file to GCode. The only problem is a common printer has three axes and, therefore, can only produce (at most) three notes at once. The obvious answer to this problem is to use more printers, and that’s what he did, as you can see below.